In an industrial robot there is an interface on the tool flange mounted on the wrist of the robot for the tool that is to be mounted thereon. This interface includes mechanical connection, electric connection and often also pneumatic connection. The present invention relates to the electric connection thereof. The electric connection normally includes a plurality of connectors that are to be individually and separately connected to a respective pole of the electric interface. To establish these connections conventionally is a time consuming operation since each individual conductor has to be mounted to its respective pole. The cabling that includes the conductors is also exposed to wear. It is therefore necessary to replace worn-out cabling at regular intervals, which accentuates the drawbacks with such a time consuming operation.
Various examples of how the connectors are arranged in relation to the tool flange are disclosed in U.S. Pat. No. 6,945,814, US 2008156137, EP 1287952 and JP 2002079487. However, none of these disclosures solves the problem how to provide the connections in a quick and safe way.
A step towards a more rational connection of the conductors to the respective poles is disclosed in WO 03015998, which relates to an industrial robot comprising a manipulator with a control system, where the manipulator comprises a hollow, first robot unit and a second robot unit rotatable around an axle. The first robot unit and the second robot unit are arranged for rotation and/or bending in relation to each other and the second robot unit includes a robot tool. Cables are drawn from through the first robot unit and arranged coaxially and detachably connected with a first end to the second robot unit via connection device. The connection device comprises a body, fixed to the first end of the cables in at least one wire and the body is arranged with sockets for connection of power supply to the robot tool.
This device however requires that the first robot part, i.e. the wrist, is hollow and that the cables are coaxial in relation to the axis. The use of a hollow wrist has the advantage that the cables and pneumatic tubing is protected from entanglement with human workers or other external objects. Since the cost for a hollow wrist is much higher than for a corresponding non-hollow wrist it is of interest to avoid entanglement by other means, which implies that the cabling cannot be drawn coaxially with the axis.